Many of the modern image/video coding standards such as the JPEG, MPEG-1, MPEG-2, and MPEG-4/H.264 video coding standards are based on a block-based compression architecture. In a block-based compression architecture, a video image is partitioned into blocks of pixels, such as 8×8 blocks of pixels, and each block is separately encoded. One of the prominent visual artifacts caused by block-based compression is the visible blocking effect created at block boundaries in the decoded images caused by coarse quantization and coefficient truncation. A process to reduce the effects of block-based compression after decoding is referred to as “deblocking.” However, conventional deblocking processes generally do not meet the visual expectations of a viewer. Frequently, an image is unnecessarily blurred by a heavy level of image filtering at block boundaries. At a light level of filtering, blurring is generally not visible, but block boundaries often remain visible.
The ability to reduce video block artifacts caused by video compression without compromising perceived image quality would answer an important market need.